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Operators must be defined on values of specific types. For instance,
+
is defined on numbers, but not on structures. Operators are
often defined on groups of types. For the purposes of Modula2, the
following definitions hold:
INTEGER
, CARDINAL
, and
their subranges.
CHAR
and its subranges.
REAL
.
POINTER TO
type
.
SET
and BITSET
types.
BOOLEAN
.
The following operators are supported, and appear in order of increasing precedence:
,
Function argument or array index separator.
:=
Assignment. The value of var :=
value is
value.
<, >
Less than, greater than on integral, floatingpoint, or enumerated types.
<=, >=
Less than or equal to, greater than or equal to
on integral, floatingpoint and enumerated types, or set inclusion on
set types. Same precedence as <
.
=, <>, #
Equality and two ways of expressing inequality, valid on scalar types.
Same precedence as <
. In GDB scripts, only <>
is
available for inequality, since #
conflicts with the script
comment character.
IN
Set membership. Defined on set types and the types of their members.
Same precedence as <
.
OR
Boolean disjunction. Defined on boolean types.
AND, &
Boolean conjunction. Defined on boolean types.
@
The GDB “artificial array” operator (see Expressions).
+, 
Addition and subtraction on integral and floatingpoint types, or union and difference on set types.
*
Multiplication on integral and floatingpoint types, or set intersection on set types.
/
Division on floatingpoint types, or symmetric set difference on set
types. Same precedence as *
.
DIV, MOD
Integer division and remainder. Defined on integral types. Same
precedence as *
.

Negative. Defined on INTEGER
and REAL
data.
^
Pointer dereferencing. Defined on pointer types.
NOT
Boolean negation. Defined on boolean types. Same precedence as
^
.
.
RECORD
field selector. Defined on RECORD
data. Same
precedence as ^
.
[]
Array indexing. Defined on ARRAY
data. Same precedence as ^
.
()
Procedure argument list. Defined on PROCEDURE
objects. Same precedence
as ^
.
::, .
GDB and Modula2 scope operators.
Warning: Set expressions and their operations are not yet supported, so GDB treats the use of the operator
IN
, or the use of operators+
,
,*
,/
,=
, ,<>
,#
,<=
, and>=
on sets as an error.
Next: BuiltIn Func/Proc, Up: Modula2 [Contents][Index]